Compilare: user.cpp: In function ‘void solve()’: user.cpp:36:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < x.size(); j++) ^ user.cpp:38:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int q = x[j], i = 0; i < a[q].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:52:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < d.size(); cout << d[i++] << ' '); ^